energy conservation can be obtained by solving problem (REF ) via HBVMs, a class of energy-conserving Runge-Kutta methods for Hamiltonian problems (see, e.g., [1]}, [2]}, [3]}, [4]} and the monograph [5]}, see also the recent review paper [6]}). Nevertheless, in the case where the problem is not Hamiltonian, HBVMs are no more energy-conserving. This motivates the present paper, where an energy-conserving variant of HBVMs for Poisson problems is derived and analyzed.
